Fig 1' Caffeic acid suppresses UVinduced IL10 mRNA expression in vivo' Mouse skin was exposed to UV

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Caffeic Acid Suppresses UVB Radiation-Induced
Expression of Interleukin-10 and Activation of
Mitogen-Activated Protein Kinases in Mouse
Fig 1. Caffeic acid suppresses UV-induced IL-10
mRNA expression in vivo. Mouse skin was exposed
to UV at the dose of 4000 J/m2 and immediately
treated with phyto-compounds at desired
concentrations. Skin samples were collected after
24 h and total RNA was isolated. IL-10 mRNA
expression was analysed by RT-PCR. CAcaffeic
acid, EGCGa key compound in tea,
HYhydrocortisone
Fig 2. Caffeic acid suppresses UV-induced IL-10
protein production in vivo. Mouse skin was
exposed to UV at the dose of 4000 J/m2 and
immediately treated with phytocompounds at
desired concentrations. Serum samples were
collected after 48 h and IL-10 protein production
was analysed by ELISA.
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Fig 3. Caffeic acid prevents UV-induced local
immune suppression. Mouse skin was exposed to UV
at the dose of 4000 J/m2 and immediately treated
with phyto-compounds at desired concentrations.
Mice were sensitized and challenged by DNFB. CHS
response was measured 48 h after challenge and
ear thickness was expressed in x 10-2 mm.
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Ultraviolet radiation present in sunlight causes
sustained immune suppression and
photo-carcinogenesis in humans. Caffeic acid
(CA), a phenolic acid present in many dietary
plants, has been shown to confer antioxidant and
anticancer activities. In the present study, we
demonstrated a protective effect of CA against UV
radiation. CA inhibited the transcriptional
activation of UV-induced IL-10 promoter activity,
IL-10 mRNA expression, and IL-10 protein
production in mouse skin. Further, CA attenuated
the local immune suppression induced by UV
radiation against a hapten, dinitrofluorobenzene.M
echanistic studies showed that CA also
significantly inhibited the UV-induced activation
of MAPK signal transduction pathways, such as
ERK, JNK and p38 and the downstream transcription
factors AP-1 and NF-?B. Our foundings suggest
that CA may confer significant protection against
UVB-induced immune suppression and
photocarcinogenesis, and these results may have
skin health care applications. Staniforth, V.,
Chiu, K.-T. and Yang, N.-S. (2006). Caffeic acid
suppresses UVB radiation-induced expression of
interleukin-10 and activation of
mitogen-activated protein kinases in mouse.
Carcinogenesis, 27(9), pp. 1803-1811.